Thronged, creaking and filthy

Bursting cities, bust infrastructure

IT IS hard to say exactly what makes for a successful city. Some can be polluted and alive, others spotless and sterile. Still, no one wants to live in a city that is impossibly congested, suffers constant blackouts and frequent floods, chops down its trees, concretes over its parks, has awful schools and hospitals, is devoid of any buildings of charm or character and is governed by corrupt politicians and incompetent civil servants. Yet many people have to.

Transport can sometimes define the form of a city, as river traffic helped shape Tudor London's Thames-side expansion, and the freeways that replaced the old light railways of Los Angeles are both the arteries and the bone structure of the modern city. Transport, too, is often the most obvious of a city's shortcomings. From Beijing to Tehran to São Paulo, streets are choked with traffic and pedestrians are choking with fumes.

The solution to this is clear: good public transport. In some places that is recognised. In southern Brazil, Curitiba, the capital of Paraná state, has been trying to keep its transport system abreast of an expanding city's needs since the 1940s, when the town got its first urban plan. In the 1970s a busy commercial street was pedestrianised—a first for Brazil—and elsewhere buses and local traffic were made to run down the centre of broad roads while faster traffic whizzed one way down either side. In the 1980s the city went increasingly green, creating parks, extending the transport system and bringing in multi-carriage buses. The transport authority collected the fares and paid the bus operator. Curitiba's buses achieved average speeds above 20kph, carrying 12,000 passengers at peak hours. Rail transport generally does better, but the buses were popular and cheap (though they have recently been losing market share).

Other Brazilian cities have copied Curitiba, but without much success. Their failure is blamed on the imperfections of democracy: the Curitiban reforms were pushed through with military backing during a dictatorship that ended in 1985, since when other cities' efforts have been stymied by the lobbying of the affected bus companies. This has always ensured that some crucial element of the scheme was missing. Yet in Quito, the capital of Ecuador, and Bogotá, that of Colombia, the Curitiba bus system has worked well, and it has been copied successfully from Jakarta to Brisbane and Ottawa to Rouen.

In most other places, though, people who can afford cars seem to prefer them. Public transport is often slow, unreliable and unpleasant. Edward Glaeser, of Harvard University, reckons that the average American commuter's journey takes 48 minutes by public transport but only 24 minutes by car. No wonder so many Americans drive to work. In Tehran petrol is heavily subsidised, so taxis are cheap, and the new metro is still far from complete. Karachi is probably the biggest city in the world without a rail network of any kind, and the buses are overloaded. Those who have the option mostly drive.

Probably the only way to get people out of their cars is to hit their pockets. Singapore was the first city to introduce road charges, in 1975. London and Oslo have followed suit (Stockholm will join them), with some success in reducing traffic. But punitive charges will work only if the displaced drivers can switch to a decent public transport system. Often they cannot.

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Some cities are trying to build rail systems, but many seem, even so, to be doomed to reliance on buses. Manila's new railway carries only 8% of the traffic; Bangkok's smart new sky train and metro only 3%; and Kolkata's metro even less. Happy the people of Copenhagen, two-fifths of whom bicycle to work.

A half-way house for many is a scooter or motorbike. Yet even these are under threat. Guangzhou, the richest city in mainland China and therefore a magnet for migrants, has recently banned mopeds and motorbikes, supposedly to reduce congestion and crime but in reality to discourage job-seeking incomers. Neither objective is likely to be achieved.

A greater folly, however, can be seen in those Chinese cities that are responding to clogged roads by building carriageways one above the other. Such places would do better to emulate Seoul, whose last mayor tore down an elevated freeway in the middle of the city and thus restored to view a long-buried river seen by the locals as a source of spiritual life. That, and his improvements to the public-transport system, have done wonders for his popularity. He now hopes to become president.

Dirty water, fetid air

Cities can be great levellers: congested streets and immobile trains hit rich and poor alike. Similarly, when Hurricane Katrina swept across America's Gulf coast on August 29th 2005, deluging New Orleans and making more than 1m people homeless, the world realised that nature could smite a rich country as easily as a poor one.

An equally sobering lesson, though, had come just a month earlier, on July 26th, when 994mm (over three feet) of rain had fallen in 24 hours on Mumbai. A third of the city was submerged, hundreds of people lost their lives and thousands of homes were destroyed. The two events should give pause for thought, for the new urge to urbanise has been matched not just by global warming but by another mass movement: a dash for the coast.

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Two-fifths of the world's cities of 1m-10m people, and 15 of the world's 20 megacities, lie on or near a coast, where many are at risk from flooding. Their vulnerability is likely to increase. London built a barrier in the 1980s to save it from the floods that occasionally saturated parts of the city when high tides and storms coincided. The barrier was raised only 27 times between 1986 and 1996. In the next ten years it went up 66 times. Forecasters say that, thanks to the rising sea level, it will go up and down ever more frequently, and may be overwhelmed by 2030.

In most cities, rich or poor, it is the less well off who are most at risk from floods and natural disasters. It was the poor of New Orleans, nearly a third of the population, who lived in the lowest-lying parts of the city and suffered most from Katrina's wrath. Similarly, it was the urban poor of Honduras and its neighbours who were smitten hardest by Hurricane Mitch in 1998. And it is the people of the slums more widely in Latin America who are most vulnerable: floods often sweep through the favelas of São Paulo, half of which stand on river banks.

In some places too little water, not too much, is the problem. China's thirst for industry and irrigation has combined with climate change to drain the aquifers, some of which hold fossil water that has lain undisturbed for millennia. Droughts seem to be ever more frequent in northern China, and southern cities such as Guangzhou are also affected. Rivers are drying up: the Yellow river now flows to the sea for only a few weeks a year. And the rain, when it comes, is intensely acid. To make matters worse, the glaciers on which both China and India partly depend are melting. Any benefits from extra water supplies will be short-term, and vitiated by floods.

No wonder water is expensive, especially for the poor. Those slum-dwellers who buy their water by the litre, whether they live in Kibera, Dharavi or a Brazilian favela, will pay more for it than their neighbours in richer districts who get it from a tap. And the water that flushes sewers is literally beyond them (in Dharavi it is actually below them: a sewer lies under the slum, but no one can afford a connection).

Only three-fifths of the people of Shanghai live in buildings connected to a sewer, and barely 3% of the inhabitants of Jakarta have access to the main drains. Most cities in the developing world discharge their sewage untreated into rivers or the sea. Delhi draws three-quarters of its drinking water from the Yamuna river, into which the city dumps quantities of sewage, almost all of it untreated, to join a cocktail of farm chemicals and industrial effluents, including arsenic.

Human ingenuity allows some people to make use of pollution. Waves of gleaners sift the sweepings of Hanoi's streets, just as children pick over the rubbish of Maputo's main tip. Every city in Asia and Latin America has an industry based on gathering up old cardboard boxes. Recycling in Mumbai is so sophisticated that the guts of dead animals are said to be collected and turned into medical sutures.

But most pollution has a cost. Dirty air, says the UN, causes the premature death of 400,000 Chinese each year. The diseases caused or carried by contaminated water kill children the world over in huge numbers. Solid rubbish is also bad for you when you literally live on top of it, as do the people of Korogocho, a Nairobi slum. And even recycling can be lethal. In China and India the destitute dismantlers of computers and electronic goods, many of which are shipped from rich countries, are often exposed to toxins.

With people pouring into the cities and cars pouring on to the roads—only 1% of Chinese own a car as yet—and with richer countries exporting many of their most polluting industries, the outlook for the environment looks grim. Yet some places have done better than others.

Bangkok provides an example of how to reduce air pollution. Fifteen years ago it was a byword for foul air, a city where the traffic stood still and anyone tempted to resort to a tuk-tuk, the local version of the Indian open-sided auto-rickshaw, risked asphyxiation. It was much like Beijing, São Paulo or Mexico City, where views are usually seen only in pictures and the atmosphere can be cut with a knife.

In Bangkok, though, a group of city officials, with notably little support from a succession of ephemeral governments, has reduced the air-pollution levels by 20-50%, depending on the measure, despite an increase in vehicles of 40% in the past ten years alone. They have done so by imposing fiercer pollution controls on cars, raising taxes on two-stroke motorbikes and making all taxis run on (subsidised) liquefied natural gas.

Natural gas has also benefited Delhi, whose air has become significantly fresher since 2002, when the Supreme Court ordered its buses to convert to gas. Delhi's air is today half as polluted as it was in 1994, and recent figures suggest that Beijing's is now dirtier. China as a whole has 16 of the world's 20 most polluted cities. But the country is starting, with varying degrees of urgency, to realise that green investment often makes sense. First, it is coming to see that the costs of inaction are huge: the UN believes environmental degradation robs the country of 12% of potential GDP. Second, it is increasingly persuaded that spending may pay off. The World Bank estimates, for example, that the $3.15 billion spent in China on flood control since the 1960s has averted losses of $12 billion.

In any event, China now proudly points to developments like Dongtan, just north of Shanghai, which is designed to be the world's first sustainable city. The claims for it may be extravagant: the city will, it is said, be self-sufficient in energy and water, green with parks, silent with electric cars and utterly in harmony with nature. But the ambitions are laudable.

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In other parts of China, too, signs of sensitivity to the environment are growing. Shanghai, Chongqing, Fatou and Xian joined with their collaborator, Denmark, to show off a series of urban innovations at the Venice architecture Biennale last year. Shenzen, whose extraordinary economic boom has been partly built on contempt for the environment, is now regarded within China as a place not to emulate. And even in much smaller cities a new environmentalism is on display: in Riuli, a free-and-easy way station on the Myanmar border, solar panels are sold almost as commonly as sex.

Richer countries are experimenting in other ways. Some cities are encouraging green buildings. Melbourne's council has commissioned “a landmark ecologically sustainable building” air-conditioned by a natural “breathing system”, which draws in cool air at night to flush out the previous day's heat, and uses vegetation to filter outside air. Chicago's mayor has put a green roof on city hall—a miniature expanse of prairie that soaks up water and absorbs heat. And Abu Dhabi, anticipating the world after oil, is investing in a huge solar-power project, part of a scheme to turn the city into a green-energy pioneer.

All this suggests that the filthy cities of the urbanising world can, and will, clean themselves up, just as the squalid cities of the rich world have done. But they cannot do so alone. In this, as in most urban matters, a collaborative national government is essential, and international help, too.